//ts编译后就是js
//强类型：强制一种类型，不可更改
var a = "123123";
a = 123;
//any可以是任意类型
var b = 123;
b = 'sdfsdf';
b.toUpperCase();
b.toUpperCase();
b = {};
b = true;
var c = true;
// void 代表空值，就是没值，undefined 或 null
var d = 123;
d = null;
d = undefined;
var e = 123;
e = null;
e = undefined;
function login(model) {
    return {
        username: 'admin',
        role: '管理员',
        token: 'sdfd123123'
    };
}
var msg = login({ username: '123123', password: '123123' });
